This invention relates to cosmetic compositions of matter in stick form, particularly to antiperspirant sticks.
In the prior art and in the market place there are solid cosmetic sticks. Solid stick antiperspirants and deodorants having astringent zirconium and aluminum compounds as the active agent are of primary concern and the invention will be treated with particular emphasis on these products, although the inventive concept has wider application to cosmetic sticks in general.
The two principal types of stick antiperspirant on the market heretofore were the solution type and the alcohol in water type. Such sticks have attained a certain degree of popularity but have certain disadvantages along with their good points.
The solution type is hard to the point of being brittle and has a tendency to break off in application. The antiperspirant consumer product is somewhat greasy and tacky due to the large amount of propylene glycol in combination with the aluminum compound.
The alcohol/water stick loses alcohol in prolonged storage, which can impair the acceptability of the product. A disadvantage felt by the user of the alcohol/water formula is a sensation of stinging and coldness on application.
Neither of the prior art market formulations is easy to apply; they are hard and drag on application. The prior art cosmetic formulations generally are of these two formula types.
There is a need for a formulation having a low melting point for easy application and having a smooth and slippery, yet dry feel. Cosmetic ingredients may be found in the prior art which exhibit one or more of the properties desired but combinations of such ingredients which are both efficacious and compatible with each other cannot be predicted. In this case, volatile silicone oils were known to be low staining and have favorable dryness and slip. Long chain alcohols were known to be hard enough to provide a useable stick. However, silicone oils and long chain alcohols in solid form are not compatible. The alcohols solidify and press out the silicone oils as liquid at room temperature. Therefore they had not been used together in a solid stick antiperspirant before this invention.